6.23-6.35 uses of radioactivity

Question 1

In a radioactive substance what decreases over time?

Answer 1

Radioactivity

Question 2

What is the unit of activity in a radioactive isotope?

Answer 2

Becquerel-Bq

Question 3

What is the half life of a substance?

Answer 3

The time taken for half of the undecayed nuclei to decay

Question 4

Can it be predicted when a nucleus will decay?

Answer 4

No

Question 5

What does half life enable us to do?

Answer 5

The activity of a very large nuclei to be predicted during the decay process

Question 6

Give three uses of radioactivty

Answer 6

.Household fire(Smoke)alarms
.Sterilising equipment
.Irradiating food
.Tracing and gauging thickness
.Diagnosis and treatment of cancer

Question 7

How is radiation used in smoke alarms?

Answer 7

.Americium is an alpha emitter
.The alpha particles ionise the air and form a current
.If smoke is detected the current drops and a sound is emitted

Question 8

How is radioactivity used in irradiating food?

Answer 8

.Gamma rays transfer energy to bacteria and kill them

Question 9

How is radiation used in sterilising equipment?

Answer 9

.Radiation exposed to the equipment kills the microbes

Question 10

How is radiation used when tracing and gauging thickness of materials?

Answer 10

.Beta radiation is mildly penetrating and can just pass through paper
.A source and receiver are placed either side of the paper
.If there is a drop or rise in electrons this means the paper/thickness has changed

Question 11

How is radiation used in the diagnosis and treatment of cancer?

Answer 11

.Consuming/injecting a tracer, it passes through the body and an external detector can picture where the tracer has collected in the body which can reveal tumours

Question 12

What’s the dangers of ionising radiation?

Answer 12

.Tissue damage

.Mutations

Question 13

What presents a larger long term risk a short or long half life?

Answer 13

A short half life

Question 14

Give two safety precautions with radiation

Answer 14

.Limiting Patient dose

.Medical personnel leave the room during x rays

Question 15

What’s the difference between contamination and irradiation?

Answer 15

Contamination lasts for a long period of time-irradiation lasts for a short period of time
Contamination-source must be transferred to an object-irradiation is when a source emits radiation and it reaches an object

Question 16

What are the two types of treatments for tumours?

Answer 16

Internal and External

Question 17

Describe the process of an external treatment of a tumour

Answer 17

.A beam of gamma radiation rotates around the body
.It continually focuses on the tumour while only momentarily passing the healthy cells surrounding the tumour
.This ensures minimal damage occurs to the healthy cells

Question 18

What’s the two problems with treating tumours externally?

Answer 18

.Long time to fully treat the tumour, taking multiple visits around 5 weeks
.Greater risk of long term side effects

Question 19

How does the internal treatment of tumours work?

Answer 19

.Radioactive material is held within a needle and is injected directly into the tumour

Question 20

What is the downside of treating a tumour internally?

Answer 20

.A longer period of time needs to be spent in hospital as some radioactive materials are highly radioactive meaning you have to reduce time spent with visitors

Question 21

What does PET stand for?

Answer 21

Positron emission topography

Question 22

What happens in a PET scan?

Answer 22

.Radioactive tracer is inserted into the body
.The tracer is tagged to the desired chemical and the tracer travels where the chemical travels
.Scanner reports where the tracer emits radiation
.This produces a 3d visualisation of the body

Question 23

What are PET scans known for?

Answer 23

.Used to show how effective current treatment is

.Or to diagnose cancer,epilepsy or Alzheimers

Question 24

Why do isotopes in PET scanners need to be produced near by?

Answer 24

.Tracer has half life of 110 mins so it cannot be stored for a long time before it decays